The glycosylation pattern of a glycoprotein often plays a significant role in the function of that glycoprotein. To give but a few examples, a glycoprotein's glycosylation pattern may affect its ability to fold correctly, its stability (e.g., resistance to proteolytic and/or other degradation), catalytic activity, pharmacodynamic and/or pharmacokinetic properties, and/or the ability of that glycoprotein to properly interact with other molecules. Alternatively or additionally, a glycoprotein's glycosylation pattern can affect transport and targeting of the glycoprotein. For example, a glycoproteins' glycosylation pattern may affect whether the glycoprotein remains intracellular (including, e.g., the correct targeting of the glycoprotein to the proper subcellular compartment or compartments), whether the glycoprotein will be membrane-bound and/or whether the glycoprotein will be secreted from the cell.
Current methods are often not able to detect glycan species that are present at low levels within a population of glycans. Major glycan species can prevent detection and identification of glycan species that are present at low levels. Furthermore, current methods usually cannot accurately quantify relative levels of individual glycan species within a population of glycans. Current methods may not be able to detect non-standard linkages within a population of glycans. Accordingly, methods to detect glycan species that are present at low levels within a population of glycans are needed. Methods to quantify relative levels of individual glycan species within a population of glycans are needed.